There is more proof that mothers who breastfeed should not drink alcohol because it could cause cognitive problems for their baby.

A new study by researchers at Macquarie University in Australia found that babies who are exposed to alcohol through breast milk may have reduced cognitive abilities by the age of 7; however, those lowered abilities were "normalized" by the age of 11.

The study tested more than 5,000 Australian children every two years until the age of 11.